Specific dynamic action of food in obese patients

Certain features of the body hormonal system participation in the realizing of the specific dynamic action of food (SDAF) were studied in 26 patients with exogenous constitutional obesity. The radioimmunoassay was used to estimate the levels of a number of hormones (gastrin, insulin, glucagon, triiodothyronine, thyrotrophin, adrenocorticotrophin and hydrocortisone) in the peripheral blood of the patients on an empty stomach (the basal level) and 1,2 and 4 hours after food protein intake. The control group consisted of 20 normal subjects. It has been shown that SDAF is a complex process of changing from the state of hunger to satiation that involves many regulatory components, both nervous and humoral. The study of the features of the SDAF development in health and disease presents valuable information on the mechanisms of metabolic disorders in the body in varying pathologic states including obesity.     

Investigation of the operation time dependence of the yield of ammonia conversion to nitrogen(II) oxide by platinum catalyst sets

The origins of changes in the catalytic activity of platinum catalysts in the ammonia oxidation process are studied. A general mathematical model for the dependence of the catalyst activity on the operation time of a single platinum gauze is proposed. Simplified expressions for the catalytic activity of two basic types of catalyst sets are obtained. Optimization of the catalyst operation mode is investigated and an optimal mode is selected based on the industrial data. © 2001 Society of Chemical Industry     

Verification of the Model of a Truck Chassis

Russian Engineering Research - The working eigenvectors of a truck chassis are determined experimentally using an electrodynamic vibrator over a broad range of exciting frequencies. A method is...     

Effects of Tyrosine and Tryptophan in Rats with Diet-Induced Obesity

Amino acids tyrosine (Tyr) and tryptophan (Trp) play a significant role in the regulation of energy metabolism, locomotor activity, and eating behavior. We studied the possibility of modulating these processes in obesity by increasing the pool of Tyr and Trp in the experimental diet. As a model of obesity, we used Wistar rats fed a diet with an excess specific energy value (HFCD) for 64 days. Trp led to a normalization of the rats’ body weight almost to the control level, but increased anxiety-like behavior and decreased long-term memory. The consumption of amino acids resulted in increased grip strength and impairment of short-term memory. The locomotor activity of animals decreased with age as a result of Tyr consumption, while Trp, on the contrary, prevented this. The Tyr supplementation led to the normalization of triglycerides and LDL. In the spleen cell lysates, amino acids suppressed the production of proinflammatory cytokines. The liver tissue morphology showed that the consumption of Tyr noticeably weakened the signs of fatty degeneration. The addition of Trp, on the contrary, led to an unfavorable effect, consisting of the appearance of a high number of large rounded fatty vacuoles. The data obtained indicate a more pronounced anti-inflammatory effect of Tyr as compared to Trp.     

A simple model of elastoplasticity for nonproportional cyclic loading

On the basis of the analysis of experimental data, we formulate requirements to the constitutive relations of plasticity under the conditions of complex cyclic loading. We propose a version of constitutive relations obtained by a simple generalization of the Mazing model to the three-dimensional case and introduction of a function of cyclic hardening. We also suggest a procedure for the identification of this function. According to the results of numerical analysis, this model adequately describes the main effects of cyclic plasticity for austenitic stainless steels. Perm State Technical University, Perm, Russia. Translated from Problemy Prochnosti, No. 1, pp. 15 – 24, January – February, 1998.     

Mass Transfer Model for Bubbling

The dynamic parameters of the gas–liquid layer and the factors determining the formation, separation, and motion of bubbles are correlated on the basis of the cell model of bubbling. The hydrodynamic and mass-transfer parameters of bubbling are presented as functions of the Reynolds, Archimedes, and Weber numbers with regard for the free cross section of the bubbler.     

Nanostructured catalytic membrane reactors of the new generation

Studied in this work were the industrially important processes (partial oxidation of methane, oxidation of methanol to formaldehyde, reduction of oxygen in aqueous media, oxidation of CO to CO₂) involving the use of nanostructured catalytic membrane reactors of the new generation. The membrane reactors were prepared according to various methods: sol-gel, molecular layering, magnetron sputtering, chemical deposition, etc. Subject to study were also the structure of the catalytic membranes and the kinetics of the reactions occurring in the gaseous and liquid phases. It was demonstrated that the deposition of a nanostructured catalytic layer to nonselective porous membranes could give rise to, or enhance, the selectivity of both their gas permeability and catalytic activity. In the case of the application of hybrid membranes, an “asymmetry effect” was discovered and explained. Some of the membranes studied can be considered as specific nanoreactors.     

A method of solution for the cyclic bending problem

A new approach to modeling processes of elastoplastic cyclic bending on roller levellers for beam straightening, levelling of long-dimensional profiles with arbitrary cross-sections, and some other applications of a similar kind, is proposed.Standard techniques for modeling the above-mentioned processes do not account for longitudinal motion, and, therefore, are not completely adequate. The stress-strain state (SSS) at every point of the material is determined not only by its position but also by its strain history.In modeling the processes of cyclic bending, use is made of the Euler-Lagrange approach to formulating the governing equations, together with traditional assumptions such as the hypothesis that plane cross-sections remain plane, stationarity of the processes, and the theory of anisotropic hardening. These allow one to take into account the strain history of moving material particles.The method developed makes possible the determination of not only the longitudinal components of the strain and stress tensors, but also the transverse components, as well as the beam profile's curvature, level and distribution of residual stresses.